803A Troubleshooting

[vrzff]

Hey all,

I'm the new owner of an 803A, and having some issues that I can't seem to solve-- or I'm too cold and defeated to think straight.

1600 hours on the clock, has fuse mod.

It took me two days to get the engine running. New fluids, filters, ect. Pulled the injector pumps, cleaned, reinstalled. Bled everything multiple times. Finally gave in to just cranking it repeatedly (15sec intervals × a dozen times in a row) and each one got me closer until it finally caught and ran. Now starts very easily, even cold.

Right now I'm having issues with the voltage output. I'm getting *maybe* ~30VAC on each phase. Contactor is closing.

When holding the crank for a extra few seconds after starting, no voltage output on the gauge. The frequency gauge pins to max until I let go to Run. No 110VAC at convenience outlets.

VR 3A fuse is blowing. Quad winding seems to be fine, outputting AC and ohms out at 1.2.

What should I really be looking at here? The whole top is off, so I have reasonably easy access to everything at this point.

 

[Jeepadict]

The experts haven't arrived yet. So while you're waiting, click your mouse into the TM section and download all the applicable manuals for your machine if you haven't done so already. There's some troubleshooting sections in them that may be of use to you.

Sent from my SM-G970U using Tapatalk

 

[Ray70]

For starters, are you sure the fuse holder has the correct fuse in it?
3A, but are you using a slow blow fuse or a fast acting one?
How long will it run before blowing the fuse, a few minutes or does it pop almost instantly?
Also, reading your post, it sounds like even while holding the switch in the crank position after it starts you still only get about 30VAC and nothing registering on the gage, but your Hz. pegs up over 65?

 

[vrzff]

The experts haven't arrived yet. So while you're waiting, click your mouse into the TM section and download all the applicable manuals for your machine if you haven't done so already. There's some troubleshooting sections in them that may be of use to you.

Thank you! I do have the manuals, and planning to check out the windings and rectifier tomorrow AM. Out of light today and can't be out in the cold any longer. It's been a long day on this thing.

For starters, are you sure the fuse holder has the correct fuse in it?
3A, but are you using a slow blow fuse or a fast acting one?
How long will it run before blowing the fuse, a few minutes or does it pop almost instantly?
Also, reading your post, it sounds like even while holding the switch in the crank position after it starts you still only get about 30VAC and nothing registering on the gage, but your Hz. pegs up over 65?

Yes, using the correct fuse per TM. It blows almost instantly, which leads me to believe components are shorted in the regulator. I drilled out the rivets, and didn't notice anything visibly wrong. Diodes looked to be in fine shape, but I didn't probe anything on the board yet.

While holding, the HZ pegs to 65+ and still only getting about 30VAC and nothing on the voltage gauge. I also directly checked the windings on TB3 while running, and getting the same.

Am I correct to believe that I should still be seeing about ~120VAC even with the regulator not functioning? I'm planning to open the cover on the generator head tomorrow and check the rectifiers per 4.10-3, along with stator winding resistance per 4.10-7.

 

[Jeepadict]

Solid bonus is, IIRC @kloppk has an upgraded aftermarket Voltage Regulator available amongst his other upgrades and gizmos for these machines.

Sent from my SM-G970U using Tapatalk

 

[Guyfang]

Go to the -24 TM and do the troubleshooting for the VR. The 3A slow blow fuse is there to protect the main gen when the VR is over volting. So if it blows, check the VR FIRST. Do the easy stuff first. Digging into the main gen to look at the diodes is not simple.

 

[Ray70]

Kurt should be here to assist you shortly!
He's your best resource for all things "VR" related.
If your VR turns out to be the issue, I 2nd the recommendation to use his updated replacement.

 

[kloppk]

T-
Good to hear you finally got it running!

If the 3A fuse keeps blowing it usually indicates the VR has failed.

Before jumping to that conclusion do the following.
1) Remove the 3A fuse

2) Disconnect wire 104C from terminal 6 of AC voltage regulator
Set multimeter to DC volts and connect positive lead of multimeter, to wire 104C. Connect negative lead of
multimeter to terminal 5 of AC voltage regulator, Start generator set. Move and
hold MASTER SWITCH in START position. Multimeter should indicate approximately 8 VDC.
What DC voltage do you measure?
If the voltage is about 8 VDC it indicates the flashing circuit is operating correctly by applying the flashing voltage to the static exciter.
If the voltage measured is about 0 volts it indicates the flashing circuit is likely NOT operating correctly. That failure would need to be investigated.
If the voltage measured is about 24 volts it indicates there is a continuity failure from the between the control cube to the static exciter or a failure of the static exciter itself. That failure would need to be investigated.

3) With wire 104C still disconnected and the 3 amp fuse still removed Start generator set. Move and hold MASTER SWITCH in START position.
Measure the AC Voltage across VR terminals 3 & 4. It should be between 108 and 132 volts AC.
What AC Voltage do you measure?

4) Shut down the generator.

5) Disconnect wire 156A from terminal 1 of AC voltage regulator Set multimeter for ohms and connect positive
lead of multimeter, to wire 156A and negative lead to terminal 2 of AC voltage regulator. Move VOLTAGE adjust
potentiometer counterclockwise to STOP position. Multimeter should indicate approximately O ohms. Move
VOLTAGE adjust potentiometer clockwise slowly while observing multimeter. Multimeter should increase
smoothly to approximately 5000 ohms.
Do get approximately the correct resistance readings?

 

[vrzff]

Thank you Kurt! I'll go through this early afternoon, and hopefully it's just the VR and there's time to grab one

Appreciate your time / knowledge, as always-- you're a wealth of information.

 

[vrzff]

Thanks everyone! Went through Kurt's steps exactly, and it was a bad regulator. New one in, and she's back to life! It's nice when the guy who makes them lives close by. Now I just need to find my set of dollhouse allen wrenches to swap the potentiometer knob.

My next question for anyone (as I read the TM) is the HZ drops nearly 5+ between zero load and 60%. I can adjust just fine to bring it back up, but it seems excessive. I'm wondering if I just need to keep running to loosen everything up-- probably hasn't had a workout in years and has signs of wet stacking.

Edit: Just remembered the droop adjust!

 

[DieselAddict]

Yea, the droop adjustment might need touching up. If it hasn't run much in a while, I'd give it some exercising before doing much adjusting. Could be just some tight linkages.

Edit - When it drops does it ever come back or do you adjust it back right away?

 

[vrzff]

Yea, the droop adjustment might need touching up. If it hasn't run much in a while, I'd give it some exercising before doing much adjusting. Could be just some tight linkages.

Edit - When it drops does it ever come back or do you adjust it back right away?

I'm going to do an 80% load for a few hours when the temperature warms up a bit.

It does respond to the load, but settles too low. I adjust it after a minute or so. I'll keep a closer eye on how it responds today. Yesterday was more of an it's finally running, can't wait to heat up my water buckets kind of day.

 

[vrzff]

Droop adjusted, and it's running like a champ.

Worked up to about ~110% load, and have been blowing carbon chunks for an hour. I'm starting to think the hard start was carbon around the valves, preventing a good seal. A little hard to start a compression engine with no compression >.>

Thanks for the help everyone! Now to install the remote start.